Hi @Dan Conger !
If you added them via import, you can revert it by going to Tools and Apps > Import Data > Revert.
If you added them manually, I'm afraid at the moment it's not possible to bulk-edit (yet), so please reach out to our Support team and they will help you with a more technical intervention.
I can tell you it's in our plans to introduce API endpoints for Leads, but they're not available yet. I'm also going to forward your bulk-editing suggestion internally to our team. Thank you!